
<template>
  <div class="goods" id="goods" name="goods">

    <div class="breadcrumb">
      <el-breadcrumb separator-class="el-icon-arrow-right">
        <el-breadcrumb-item to="/">首页</el-breadcrumb-item>
        <el-breadcrumb-item>全部资源</el-breadcrumb-item>
        <el-breadcrumb-item v-if="search">搜索</el-breadcrumb-item>
        <el-breadcrumb-item v-else>分类</el-breadcrumb-item>
        <el-breadcrumb-item v-if="search">{{search}}</el-breadcrumb-item>
      </el-breadcrumb>
    </div>


    <!-- 分类标签 -->
    <div class="nav">
      <div class="product-nav">
        <div class="title">分类</div>
        <el-tabs v-model="activeName" type="card">
          <el-tab-pane
                  v-for="item in categoryList"
                  :key="item.category_id"
                  :label="item.category_name"
                  :name="''+item.category_id"
          />
        </el-tabs>
      </div>
    </div>
    <!-- 分类标签END -->

    <!-- 主要内容区 -->
    <div class="main">
      <div class="list">
        <MyList :list="product" v-if="product.length>0"></MyList>
<!--        <img src="../assets/imgs/cat.jpg">-->
        <div v-else class="none-product">无相关资源</div>
      </div>
      <!-- 分页 -->
      <div class="pagination">
        <el-pagination background layout="prev, pager, next" :page-size="pageSize" :total="total" @current-change="currentChange"></el-pagination>
      </div>
      <!-- 分页END -->
    </div>
    <!-- 主要内容区END -->
  </div>
</template>
<script>
  export default {
    data() {
      return {
        categoryList: "", //分类列表
        categoryID: [], // 分类id
        product: "", // 商品列表
        productList: "",
        total: 0, // 商品总量
        pageSize: 15, // 每页显示的商品数量
        currentPage: 1, //当前页码
        activeName: "-1", // 分类列表当前选中的id
        search: "" // 搜索条件
      };
    },
    created() {
      // 获取分类列表
      this.getCategory();
    },

    watch: {
      // 监听点击了哪个分类标签，通过修改分类id，响应相应的商品
      activeName: function(val) {
        if (val == 0) {
          this.categoryID = [];
        }
        if (val > 0) {
          this.categoryID = [Number(val)];
        }
        // 初始化商品总量和当前页码
        this.total = 0;
        this.currentPage = 1;
        // 更新地址栏链接，方便刷新页面可以回到原来的页面
        this.$router.push({
          path: "/goods",
          query: { categoryID: this.categoryID }
        });
      },
      // 监听搜索条件，响应相应的商品
      search: function(val) {
        if (val != "") {
          this.getProductBySearch(val);
        }
      },
      // 监听分类id，响应相应的商品
      categoryID: function() {
        this.getData();
        this.search = "";
      },
      // 监听路由变化，更新路由传递了搜索条件
      $route: function(val) {
        if (val.path == "/goods") {
          if (val.query.search != undefined) {
            this.activeName = "-1";
            this.currentPage = 1;
            this.total = 0;
            this.search = val.query.search;
          }
        }
      }
    },
    methods: {
      // 返回顶部
      backtop() {
        const timer = setInterval(function() {
          const top = document.documentElement.scrollTop || document.body.scrollTop;
          const speed = Math.floor(-top / 5);
          document.documentElement.scrollTop = document.body.scrollTop =
                  top + speed;

          if (top === 0) {
            clearInterval(timer);
          }
        }, 20);
      },
      // 页码变化调用currentChange方法
      currentChange(currentPage) {
        this.currentPage = currentPage;
        if (this.search != "") {
          this.getProductBySearch();
        } else {
          this.getData();
        }
        this.backtop();
      },
      // 向后端请求分类列表数据
      getCategory() {
        this.$axios
                .post("/api/product/getCategory", {})
                .then(res => {
                  const val = {
                    category_id: 0,
                    category_name: "全部"
                  };
                  const cate = res.data.category;
                  cate.unshift(val);
                  this.categoryList = cate;
                })
                .catch(err => {
                  return Promise.reject(err);
                });
      },
      // 向后端请求全部商品或分类商品数据
      getData() {
        // 如果分类列表为空则请求全部商品数据，否则请求分类商品数据
        const api =
                this.categoryID.length == 0
                        ? "/api/product/getAllProduct"
                        : "/api/product/getProductByCategory";
        this.$axios
                .post(api, {
                  categoryID: this.categoryID,
                  currentPage: this.currentPage,
                  pageSize: this.pageSize
                })
                .then(res => {
                  this.product = res.data.Product;
                  this.total = res.data.total;
                })
                .catch(err => {
                  return Promise.reject(err);
                });
      },
      // 通过搜索条件向后端请求商品数据
      getProductBySearch() {
        this.$axios
                .post("/api/product/getProductBySearch", {
                  search: this.search,
                  currentPage: this.currentPage,
                  pageSize: this.pageSize
                })
                .then(res => {
                  this.product = res.data.Product;
                  this.total = res.data.total;
                })
                .catch(err => {
                  return Promise.reject(err);
                });
      }
    }
  };
</script>

<style scoped>
  .goods {
    background-color: #f5f5f5;
  }
  /* 面包屑CSS */
  .el-tabs--card .el-tabs__header {
    border-bottom: none;
  }
  .goods .breadcrumb {
    height: 50px;
    background-color: white;
  }
  .goods .breadcrumb .el-breadcrumb {
    width: 1225px;
    line-height: 30px;
    font-size: 16px;
    margin: 0 auto;
  }
  /* 面包屑CSS END */

  /* 分类标签CSS */
  .goods .nav {
    background-color: white;
  }
  .goods .nav .product-nav {
    width: 1225px;
    height: 40px;
    line-height: 40px;
    margin: 0 auto;
  }
  .nav .product-nav .title {
    width: 50px;
    font-size: 16px;
    font-weight: 700;
    float: left;
  }
  /* 分类标签CSS END */

  /* 主要内容区CSS */
  .goods .main {
    margin: 0 auto;
    max-width: 1225px;
  }
  .goods .main .list {
    min-height: 650px;
    padding-top: 14.5px;
    margin-left: -13.7px;
    overflow: auto;
  }
  .goods .main .pagination {
    height: 50px;
    text-align: center;
  }
  .goods .main .none-product {
    color: #333;
    margin-left: 13.7px;
  }

</style>